Process of preparing titanic oxide from titanic ores



Patented Jan. 10, 1928.

UNITED STATES I PATENT OFFICE.

Jnmn'ms, or BERLIN, AND rnrrz comma, or cnmomnnnune-nnnmr,

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PROCESS 01' ZFREPARING TITANIC OXIDE no]: TITANIC OBIS.

No Drawing. Application filed April 28, 1923, Serial No. 6316,3195, and in Germany December 14, 1921.

This invention has reference to a process oi obtaining titanic oxide from titanium containing ores and other raw material, and

w it is in particular intended to provide means lll' ill

Illil necessary to 'suppl ior the economical employment and for the recovery oi the sulphuric acid used in the decomposition oi the ores or the like. in the treatment oi titanic ores tor the manuiacture oi titanic oxide sulphuric oxide u," acid and only small amounts oi iron. This object is accomplished by carrying on the decomposition oi the titanic oxide ore in such quantities oi liquid that a titanium solution is obtained vvhilc iron sulphate itseli remains iuidissolvcd or is removed by crystallisation edected upon cooling the hot solution oi the decomposed raw material. "lihe about ltl per cent strong sulphuric acid resulting irom this ressuretreatment may novv be enriched with sulphuric acid Which may be readily produced in the vvell lniovvn manner ior instance by the roasting oi the sulphate oi iron obtained, so that the sulphuric acid becoes again adapted ior the treatment oi the titanic ores. it is only the-unavoidable small mechanical losses o sulphuric acid.

The process is preierahly carried out by hrst treating the titanic ores with sulphuric acid, the resulting product being then dissolved by means oi the mother liquors obtained in previous stages oi the Working oi the process in such a manner that the larger portion oi the iron is crystallized out as ironsulphate on cooling. The mother liquor which is thereby obtained and which in poor in iron is submitted to decomposition in the autoclave, and the sulphuric acid resulting thereirom which only contains rm amounts of iron, but no titanium is utilized for the absorption of the sulphuric acid angiydride obtained in the roasting oi the dri ferrous-sulphate, and also ior the absorption oi the sulphuric acid anhydride produced irom the sulphur-dioxid obtained y the roasting oi the ierrous-sulphate, aiter oxidizing the same by a contact process. "llhe 8U thus obtained either directly or in directly irom the ierrous-sulphate is sadicient to enrich the mother liquor irom the autoclave in sulphuric acid to such an eutent that it may he used over again ior the do: composition oi nevv portions oi titanic ores. Evidentl one may also proceed by using a cold met or liquor, saturated with ierroussulphate tor the extraction oi the decomposed ore, instead oi dissolving it hot, the cold extraction being carried on so as to cause only the titanium salt to be dissolved. Then the iron may also be eliminated irom the cycle oi liquids only alter the precipitation oi the titanium in the autoclave, when those liquids have been enriched With sulphuric acid. llron sulphate is Well linovvn to be diflicultly soluble in concentrated sulphuric acid.

in case the titani solutions should con tain trivalent iron it should he converted into bivalent iron heiore the splitting and in accordance with the tier this purpose either the electrolytic reduction or the reduction by means oi metallic iron are best adapted because they do not introduce any ioreii matter into the liquor so as to avoid the possible accumulation oi iorei atter in the cycle which the li uor undergoes in accordance with this invention. The iron sulphate thus obtained contains a lare proportion oi the sphuric acid in tronced into the decomposed ore in an easily recoverable and available condition. v

The process according to this invention may obviously with corresponding charges, he also carried out ii a certain portion oi the iron has already been removed irom the titanic ores by any other methods, such as icr; instance by corine and hydrochloric acid. such case it is sometimes not necessary to remove the ierrous sulphate at every cycle at the sulphuric acid action.

hhimaple i.

About one thousand kilograms oi titanium-iron-ore are mixed with about twothousand lnilograma oi concentrated in l usual methods. r

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phuric acid, and are decomposed. by heating to fusion. After a certain amount of cool but while still hot the fused mass is disso ved in' about one thousand kilo ams of water, the solution is allowed to sett e, and is submitted to a reduction operation. By cooling the solution about 1500 kilograms of ferrous-sulphate may be separated out. The mother li nor is decomposed inthe autoclave, and e resulting sul huric acid which is free from titanium an which still contains only a few per cent of iron sulphate, is enriched with sulphuric acid in the manner described, and may be used for another ll treatment.

In order to carry on the removal of the disturbing admixtures of iron still further, it has been found to be. of advantage to carry on the hydrolytic decomposition at an in-.

II creased tem erature under pressure. In accordance w1th the invention it has been found that titanic oxide free from iron may also be separated from the liquors obtained from the decomposed mass containing large 18 amounts of iron, by heating the solutions which should contain less than 5 per cent of the total amount of titanium as trivalent titanium up to temperatures of about 150 to 210 de s (3., under presure. The ti- '9 tanic oxi e thus obtained is substantially free from iron. In this hydrolytic decomposition under premure there is the further advan of an increase in the yield of titanic -qxide, because the loss is trivalent titanium-compounds which are not precipitated in the hydrolytic decomposition, is only slight, while the amount of reduction agents required is decreased.

E'wmple I I The procedure of operation is the same as in the previous Exam le I with the difference, however, that t e splitting in the autoclave is carried out at temperatures over 210 degrees C.

The titanic oxide obtainedin accordance with the process described presents the further advantage that there is no necessity of highly heating it when the oxide is converted into a well coating color pigment which is not affected by light. Careful heating to temperatures below 850 degrees C. is suflicient. i

Any. small amounts of sulphuric acid still adhering to the titanium oxy-hydrate or oxide obtained by hydrol sis, and which, as is well known, have a upon 011s and varnishes even in the dark,

ecomposing action thereby producing yellow coloration, are preferably removed in one of the stages of 00 the process according to any well known method. r v

The titanium oxide thus obtained which is of excellent covering and coating qualities is articularly well adapted for admixture wit other substances of inferior covering qualities for the manufacture of white and colored pigments.

The invention has been described in its broad aspects, but it is .to be understood that it is capable of alterations and modifications withln the scope of the claims, so as to adapt the same to varying conditions of application.

We claim:

1. The process -of producing titanium oxide from a titanium ore containing iron, which comprises reacting u on such ore with concentrated sulphuric acid, in the proportions of substantially one part of ore to two parts of sulphuric acid and thereafter subjecting the reaction mixture to thorou h contact with water in the proportion of siibstantially one part of water to each part of ore treated, subjecting the solution to a reducing agent .to reduce the ferric sulphate to ferrous sulphate, eliminating ferrous sulphate bycrystallization from the solution, and thereafter subjecting the mother liquor therefrom to a temperature above 150 C. no in an autoclave under pressure to precipitate the titanium oxide.

2. The process of producing titanium oxide from a titanium ore containing iron, which comprises reacting upon such ore with hot concentrated sul huric acid, in the proportions of substantially one part of ore to two parts of sulphuric acid, and thereafter subjecting the reaction mixture to thorough contact with water in the proportion of substantially-one part of water to each part of ore treated, subjecting the solution to a reducing agent to reduce the ferric sulphate to ferrous sulphate, eliminating ferrous sulphate by crystallization from the solution, thereafter subjecting the mother liquor therefrom to a temperature of at least 150 C. in an autoclave under pressure to precipitate the titanium oxide, and adding concentrated sulphuric acid to the mother liquor to enable it to be used for another treatment.

In testimony whereof we afiix our signatures.

JEAN DANS. FRITZ SOMMER. 

